Coaster-brake.



, F.'B.BROCKV..

COASTER BRAKE.

APPLICATION FILED FEB. 20, 1915.

. Patented Apr, 8,1919."

5 e s s m 1 v w AA, Fig. 1;

- UNITED STATES PATENT I E- memos IB. BROOK, or WASHINGTON, DISTRICT OF COLUMBIA.

E COASTER-BRAKE.

simplify structures of this class. In connection with this. simplification, a decidedly strong, durable and positively-acting mechanism is produced. The nature and advantages of the invention'will be further explained as much as is necessary in connec- .tion with the following detailed description ofan exemplifying embodiment. This embodiment is the best I have produced up to this time, but it is to be understood that the invention iscapable of. embodimentin difierent forms, and L do not limit myse1f to. details except as claimed hereinafter.

:7 Figure 1 -is'a side view ofa device embodying the invention, the hub being shown in section; I 3 n v I Fig. '2 is a longitudinal section.

s Fig. 3. atransverse; section on the'line Fig. 4 is a transverse sectionon the line .BB, Fig. 1.

Reference character l designates an axle to be secured in the usual'rear forks 2 of a bicycle or other structure. 'U'pon this axle is revolubly mounted driver 3 which carries sprocket 4; to be driven, by a chainfrom the usual crank-shaft sprocket. Otherwise the driver mayj'be propelled by bevel gears or other suitable driving means, "The driver provides a suitable bearingfi for one end of f wheel 6, The'other end of the hub has a bearing 7 upon 'a station-arymember Scarried by the axleg,The driver has apart 9 extending within'hub 6 2111(11113011 this part '9 is formed helically-inclined or wedge-like threads 10. Mounted withini the hub and having normally. a running clearance therein is a longitudinally splitsleeve 11 havingin- 'ternal threads '12 engaging and cooperating withthreadslQof the driver. Fig. 1 shows the longitudinal: divisionll of sleeve-11at one;-side thereof,,to render. the sleeve expansible when properly acted upon 'At one end the-hub is provided with a member 13 to engage one :en-dof sleeve 11' and toward the opposite end of the sleeve is a member Specification of Letters Patent.

Patented Apr. 1919.

Application filed February 20, 1915. Serial No. 9,606.

' 141:0 b-eengaged'bythe adjacent end of the sleeve. V 7 g Upon rotating the driver forward, or' so that its top moves away from the eye in Figs. 1 and 2, the driver threads 10 first move rotarily in relation to thethreads of sleeve 11 and the sleeve isshifted slightly to the right as seen insaid fi res until its right hand end engages mem' er, 13 'offthe hub. Further rotation ofjthe driver then, by reason of the wedge-like engaging faces of the driver and sleeve threads, cause'sj.ex-. pansion of the sleeve, which engages and drives the hub forward. In addition to the driving engagement afforded by thelexpansion of the sleeve, a drivingeifort is imparted to the hub by engagement of the end of the sleeve with the hub.,

In cases where it is desired tomake the contact between the end of the sleeve and the hub flange 13 more positive, the sleeve may be; provided with serrations 01' teeth 15 to engage the flange,and, further, the flange may in some cases, if desirable or necessary,

be provided :with corresponding serrations 1or' teeth (not shown) When the driver 3 is held stationary, the

forwardrotationof thehub dmoves: sleeve 11 forward rotarily in relation to the driver member 9, thus causing the action of the threads on the driverand sleeve to move the sleeve promptly to the left and at the same time. permitting the sleeve to contract. The hub is then free from the. sleeve andwill coast freely.

.Toretard orstop the wheel, the driver is moved rearward; thatis, the top is moved toward the eye in Figs. 1 and 2.- Relative rotary movement "between the driver threads and sleeve 11 at first. causes the sleeve to move to the left until its end engages stationary member 8. Further rotation of the driver in the same direction then causes ex- 7 pansion; of the sleeve by the wedgin-gaction of the threads as previously described, and.

the sleeve thus engages the interiornof the hub with brakingfriction, which may be in-' creased. by increasing the backpressure on the driver to retard the wheel to any.. extent or to stop it. In many cases it is desirable or necessary to Provide the stationary. member or brake holder 8 with serrations or'teeth 1:6

to cooperate with serrations or teeth 17' on the adjacent end ofsleeve 11. Inthis way, e v

when the sleeve is shifted to the .left to engage member 8, it is withheld from rotation further rearward rotation of the driver to be positively effective to expand the sleeve for braking and after braking contactls established between the sleeve and the hub the engagement of these serrations positively prevents the forward rotation of the sleeve under the frictional forward turning efl'ort of the hub and relieves the rider of the strain of supporting the sleeve against forward rotation during braking.

In many cases the distance between the ends of the sleeve and the hub flange 13 and holding member 8, respectively, when the sleeve is in coasting or neutral position, may be made very small and the effect of rotating the driver so as to move the sleeve away from driving position or away from braking position, as the case may be, Wlll be sufiicient to carry the sleeve to the other position so that itsengagement in said other position will be sufficiently positive without the provision of special means for that purpose. In addition to this, the hub will usually be supplied with grease or other lubricant having more or less viscosity, and the yieldable connection, so to speak, afforded by said lubricantrbetween the sleeve 11 and hub 6, or between the sleeve and some other part in respect to which it has rotation, will 'exerclse upon the sleeve an initial retarding effect so that whenever the driver is manipulated to move the driver threads in either direction, the sleeve will at first be retarded and relative movement of the driver threads and the sleeve threads will be insured and the sleeve thus certainly moved in the required direction until it engages either with the hub flange 13 or the stationary holding member 8.

Also, in some cases, the parts may be fitted in such a manner that sleeve 11 has slight frictional contact with the hub when in coasting or neutral position, and such contact will be sufficient to insure proper shift- In other cases, the holding member 8 and the sleeve may be so constructed and arranged as to insure proper shifting. For example, as shown in Fig. 5, the holding member 8 may have a tapered portion 8 adapted to frictionally engage the adjacent end of sleeve 11 as soon as the sleeve moves sufliciently away from driving position to disengage the hub or the hub flange. The

frictional engagement between the sleeve and the holding member 8 so established will positively serve to carry the sleeve into braking position whenthe driver is turned farther to the rear, and similarly when the driver is again moved forward for driving this frictional engagement will cause the sleeve to move positively to driving position and when in driving positionthe sleeve will be entirely disengaged from member 8*, so that no friction will then be created.

As clearly shown in Fig. 2, the construction may be such that the driver may be easily inserted through one end of the hub while therdriver sleeve may be freely inserted through the other end. The disclosed embodiment is such, also, that the sleeve may, if desired, be made reversible so that it is of no consequence which end is inserted first. Both ends of the sleeve for instance may be provided with serrations to engage flange 1'3 and holder 8, respectively. The sleeve threads 12 may extend the full length of the sleeve if desired, or otherwise may extend only far enoughto provide the neoessary movable contact with the driver thread 10;

The holding member 8 is to be irrevolubly fixed in the vehicle forks in any convenient way; for instance, by means of serrations 18, locked against the forked side by a' nut 19 on the axle. Otherwise, a brace arm or other device may extend from'ho'lder 8 and engage a part of the frame to prevent rotation. The bearings are usually ball bearings and are adjusted, and the adjustment is secured in a manner well understood by personsiskill'ed in the art. x

The helical threads may be wedge-shaped upon one side-only and straight upon the other, so that an expanding-movement may be given to sleeve 11 by the wedge-shaped side of the threads and a longitudinally shifting movementto the sleeve by the straight side thereof.

1. In coaster brakes for bicycles and the like, the combination of an axle, ahub driver having wedge-like threads, a sleeve 7 within the hub and having threads cooperating with the driver threads, the threaded part of-thedriver being located substantially midway between the ends of the sleeve to expand the sleeve uniformly without the action of other expandin means, a member on the hub to beengage by one end of-the sleeve and a stationary holding member to be engaged by the other'end of the sleeve.

2. In coaster brakes for bicycles and the like, the combinationof an axle, a hub, a driver having helical wedge-shaped threads located within the hub, an expansible sleeve within the hub having threads cooperating with thedriver threads, an abutment carried by the hub to. cooperate with one end: of the sleeve, an irrevoluble abutment for the other end of the sleeve, said abutment having frictional contact with the sleeve when the latter moves away from driving position.

3. Ina coaster brake the combination with the axle, hub, driver and stationary brake holding member "of a unitary expansible longitudinal split driving and braking sleeve and braking sleeve interiorly threaded adapted at one end to cooperate With the throughout its length diametrically resilient stationary braking member and at the other and split longitudinally.

end to engage a part of the hub and coop- FENELON B. BROCK. erating Wedge-like screw threads on the Witneses: driver and sleeve. D. M. SMITH,

' 4. In a coaster brake, a combined driving M. A. WOOD.

copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Iatents,

Washington, D. G. 

